package com.example.demo;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class test {
    public static void main(String[] args) {
        System.out.println(1<<30);
        Map<String, String> channels = new ConcurrentHashMap<>();
        channels.get(null);
        String a = null;
        System.out.println(a+"");
    }
}
